Method of taking oriented cores



May 18, 1937.

W. L. CHURCH METHOD OF TAKING ORIENTED CORES Filed Aug. 27, 1936 2,080,978 mn'rnon or TAKING omnu'ran corms Walter L. Church, Houston, Tex

C-M-P Fishing Tool Corporation,

assignor to Harris County, Tex., a cflrlwration of Texas Application August 21, 1936, Serial No. 98,147

2 Claim.

This invention relates to an apparatus and method for taking cores and ascertaining the natural .inclination of earth strata.

In the drilling of oil wells it is desirable to know the direction of inclination, or dip, of the earth strata in order to ascertain the location of the oil sandor oil pool.

At the presentutime it is common practice to drill a number of wells at different polntsin the same vicinity to the same formation and by comparing the depths at which a given formation is encountered in the various wells the direction of inclination or dip of the formation can be readily, or approximately, ascertained. This, however, is an expensive method of obtaining the desired information. It is an object of this invention to provide an apparatus by means of which the direction of the inclination of a given stratum may be ascertained.

It is another object of the invention to provide a novel type of core taking apparatus having a removable core barrel with means for locating the core barrel in a predetermined relation with the drill stem.

The invention also comprehends a novel method for taking cores or samples whereby its direction of inclination of earth strata may be accurately ascertained.

With the above and other objects in view the invention has particular relation to certain novel features of construction operation and arrangement of parts and a novel method an example of which is given in this specification and illustrated in the accompanying drawing whereby:-,

Figure 1 shows aside elevation of the upper portion of the apparatus shown partly in section.

Figure 2 shows a side view of the lower end thereof shown partly in section.

Figure 3 shows a cross sectional view taken on the line 3-3 of Figure 1 and Figure 4 shows a side elevation of the complete apparatus. 1

Referring now more particularly to the drawing wherein like numerals of reference designate the same parts in each of the figures the numeral I designates the drill stem to the lower end of which any conventional type of drilling tool 2 may be attached, said tool having channels as 3 through which the flushing fluid may pass from the drill stem to the cutters at the bottom of the well.

The drill will be usually attached to the stem proper by means of a tubular drill collar 4 which, in eflect, forms a section of the drill stem. The upper end of the drill collar is formed with an internally threaded box 5 to receive the pin 6 of the tool joint member proper is connected to the drill collar.

The tool joint member 1 is thickened inwardly as more accurately shown in Figure 3 and is tubular in form. It has the vertical channels 8 e and the vertical inside key-way 9.

The drill 2 has a central axial core Ill toreceive the lower end of the core barrel ll, said core barrel preferably extending. beneath the drill 2 and having its'lower end formed into a core former l2 which contains a conventional core catcher Ill. The core barrel may be supported in the drill by means of an external shoulder H thereon which lands on the upper end of the drill as shown in Figure 2.

1, whereby the drill stem Attached to the upper end of the core barrel I ll there is a cylindrical head l5 whose lower end is provided with a 'vertical bore l6 terminatin in side outlets l'l. Secured in the lower end of the bore it there is a tubular valve seat l8 having a passageway therethrough which is controlled by the upwardly opening ball valve l9. As the core or sample enters the lower end of the core barrel the air or liquid in the barrel above will be forced out past the valve l9 into the passageway between thecore barrel and the drill collar 4. The head l5 fits rather snugly through the central passageway in the tool joint member I.

The head l5 has a side slot 2| which is flared upwardly and whose upper end extends entirely transversely through the head. Pivotally mounted in this-slot there is a latch 22 whos upper end is widened forming a key 23 which normally proiects out beyond the head. The lower end of the latch is-formed with an outwardly directed catch 24 and saidlower end is seated against a coil spring 25 which is housed within the head and which normally holds catch 24 in engagement with the lower end or the tool joint member I.

The core barrel with the head I! thereon may be dropped from the ground surface through the drill stem I and will pass on down through the tool joint member 1 and the shoulder M will land on the upper end of the drill 2. As the head I! passes through the tool joint member I the sloping face 26 on the lower end of the latch 22 will strike against the upper end of the tool joint member 'I and will retract the key 28 as well as the catch 24 within the head and when said catch 24 clears the lower end of the joint member 'I the spring 25 will force said catch'outwardly underneath the lower end of the Joint member I.

- When the core barrel II is so dropped in place the key 23 may not align with the key-way 9 but, with the drill 2 on bottom, upon turning the drill stem the core barrel ll will remain stationary until the key 22 registers with the key-way 9 whereupon said key will be projected, by the spring 25, into the key-way 9 and thereafter the core barrel will rotate with the drill.

The upper end of the latch 22 has a triangular opening 21 one side, 28, of which is diagonal. A release yoke 29 is fitted through a vertical bearing in the upper end of the head and its lower end is provided with the spaced arms 30 which embrace the upper end of the latch. A release rod 3! has its ends anchored to the arms 30 and extends through the opening 29. The upper end of the yoke has a conical shaped head 32 thereupon.

When a core or sample has been taken a conventional type of over-shot 33 may be lowered into the drill stem by means of a suitable cable 34 and engaged with the head 32. Upon initial upward pull the yoke 29 will be moved upwardly and the rod 3i will ride against the diagonal margin 28 of the opening 2'! thus actuating the latch 22 to release the catch 24 from the lower end of the tool joint member I whereupon the core barrel may be withdrawn to the ground sur 4 face.

While the core is being taken drilling fluid may be forced downward through the drill stem and through the passageways 8 and 20 and out through the channels 3 to the bottom of the bore.

In carrying out the method the drill stem is lowered through the rotary drilling machine 35,

- on the derrick floor 36 and through the well casm :1. When the drill stem is started into the 40 well the position of the key-way 9 is noted. For

the purposes of this explanation it will be assumed that the key-way 9 is located toward the north. A marking, such as 38, is made on the upper end of the made up portion of the drill stem preferably in direct alignment with the keyway '9 and as additional sections are added another marking 39, in vertical alignment with the marking 38 is placed on the upper end of each additional section as added. These markings are 50 maintained in vertical alignment as made, preferably by the use of a transit stationed at a convenient point from the well so that when the bit 2 lands on bottom the position of the key way 9 will be known, that is in the present illustra- 55 tion it will be directed toward the north. The

drill stem is then elevated a suflicient distance to lift the drill off bottom and the core barrel H is then dropped through the drill stem from the ground surface. It will pass downwardly through 6 the drill stem until the shoulder l4 lands on the upper end of the drill 2. The catch 24 will there- 2,oao, o7s

upon engage underneath the lower end of the joint member 1 said projection being long enough to engage said lower end irrespective of whether the key 23 is located in the key-way 9 or not. Thecore barrel wfll thereby be locked in place. The drill stem l is then rotated to begin drilling in the usual way and if the key 23 is not already' seated in the key-way 9 it will seat therein when said key-way comes into registration with said key and thereafter the core barrel II will be locked to rotate with the drill stem I. As drill- 4 ing progresses a core will be formed by the core former I 2 and the core will pass up into the core barrel. .A sample of the strata, such as shown M in Figures, will pass up into the core barrel and be engaged by the core catcher l3.

When a sufliclent core has been taken the overshot 33 may be lowered into the drill stem and engaged with the head 32 and the core barrel with the sample therein may be withdrawn from thedrill stem. The sample contained in the core barrel, or at least the lower portion thereof, will disclose the type of earth strata from which the core was taken and by a comparison of the position of the key 23 with relation to the position of the marking 38 the direction of inclination of the strata contained in the sample in the core barrel can be readily ascertained and this will be the same asthe direction of inclination .of the earth strata from which the core was taken.

What I claim is:-

l. The method of taking a sample of the earth formation in a well which comprises lowering a drill stem and drill into the well in a predetermined position, lowering a core taking apparatus through the drill stem, operatively connecting the core taking apparatus with the drilling apparatus,

and in a predetermined position relative to the drilling apparatus, rotating the drilling apparatus to form a core and to cause the core to enter the core taking apparatus, withdrawing the core taking apparatus and core to the ground surface, relating the core, as taken, to the predetermined position of the drill stem to determine the natural inclination of the core strata.

2. The method of taking a sample 'Of the earth formation ina well which comprises lowering a drilling apparatus'including a tubular drill stem, in a selected position into the well, lowering a sample taking apparatus, including a sample receiver, through the stem into position to take a.

sample and in a selected position relative to the drilling apparatus, operating the drilling apparatus and sample taking apparatus in unison to effect the entrance of a sample of the formation into the receiver, withdrawing the receiver and entrapped sample to the ground surface, relating the withdrawn sample with said selected position of the drilling apparatus to determine the natural inclination of the strata of the sample.

WALTER L. CHURCH. 

